Monitoring printer via network

ABSTRACT

Amounts of expendables consumed by a printer are sensed accurately. A job control unit  106  transfers a print job queued in job buffer  107  to a spooler  105 , in page units. Spooler  105  sends the print job to a printer PT, as well as providing a completion determination unit  103  with notification of start of printing. Upon receiving notification of start of printing, the completion determination unit monitors the status of the printer PT and remaining data in the spooler  105 , and in the event that printer PT status is “ready to print” and there is no remaining data in the spooler  105 , decides that printing has completed, and counts the number of sheets of paper. An ink amount measurement unit  104 , by means of predetermined correcting means, corrects the amount of ink consumed during printing, so as to approximate the amount of ink actually used in printing. A server SV is notified of the number of sheets of paper and the corrected amount of ink consumed, whereupon the server performs a billing process.

TECHNICAL FIELD

The present invention relates to a technique for monitoring a printervia a network, and more particularly to a technique for monitoring thestatus of expendable supplies for a printer, and/or service status ofthe printer.

BACKGROUND ART

To date, there has been proposed a business model in which a printer isloaned to a user, whose is then charged according to consumed amounts ofexpendable supplies such as ink and printer paper. In the context ofsuch a business, it has also been proposed to remotely monitorconsumption of expendables via a network.

Exemplary methods for identifying amount of ink consumed includemathematical calculation, and monitoring with sensors. With the formerapproach, the amount of ink ejected in drops by the print head, and theamount of ink suctioned out during maintenance processes, are added upby a software application, to arrive at calculated ink consumption. Forthe latter, a method wherein two electrodes are provided for monitoringliquid level is known.

The number of pages is counted at the point in time that a print job issent from the spooler to the printer, at which point printing of theprint job is deemed finished.

However, methods involving mathematical calculation of amount of inkconsumed have the drawback that undeniable error can occur betweencalculated values and actual ink consumption, due to differences inpressure within ink cartridges or in ink viscosity due to differences infactors such as service environment (e.g. humidity and temperaturelevels in the service area), elapsed time since the ink cartridge wasfirst unsealed, or frequency of use at the user site. Another drawbackis the high cost entailed in providing each ink cartridge with a sensorable to continuously measure ink consumption.

Another problem pertaining to counting pages is that even if an errorshould occur after transfer of the print job to the printer, the systemwill nevertheless decide that printing has been finished, and willaccordingly include in the paper count those pages which could notprint, designating this count be the number of sheets of paper actuallyconsumed.

In other words, in the prior art, error is present in the estimatedamounts of expendables consumed by the printer. A similar problem ariseswhenever consumption status of expendables is monitored over a network.

With the foregoing in view, it is an object of the present invention toprovide accurate sensing of amounts of expendables consumed by aprinter.

DISCLOSURE OF THE INVENTION

The present invention in a first aspect thereof provides a monitoringdevice for monitoring a printer, comprising: a measurement unit formeasuring amount of an expendable consumed during execution of printingby the printer; a correction unit that, by means of sensing consumedamount of the expendable using a method different from the measurement,corrects error occurring in the measurement result; and a notificationunit for notifying another network-connected device of informationrelating to the consumed amount reflecting the correction.

The amount of an expendable consumed is calculated and monitored by theminute during execution of printing. However, depending on the serviceenvironment of the printer, there may be discrepancy between estimatedconsumed amount of an expendable, and the actual consumed amount. Thecorrection unit performs a process to correct this discrepancy, so as toapproximate actual consumed amount used by a user.

“Method different from the measurement” herein can be carried out atpredetermined timing established on the basis of remaining amount of theexpendable product, the number of print operations, or the like, by amethod wherein the remaining amount or status of the expendable issensed by means of a sensor or the like. In preferred practice, sensoraccuracy will be higher than that of measurements made by themeasurement unit. Using sensor values, measurements made by themeasurement unit can be corrected. Examples of predetermined timingherein include when a measurement indicating that half of the expendableremains is calculated, or when a predetermined number of printoperations have taken place.

The notification unit affords notification of amount consumed, thisamount reflecting the aforementioned correction. Notification maycontain, for example, information identifying a printer, informationidentifying a user, or the like as appropriate. Information identifyinga printer could consist, for example, of the printer's MAC address or,where connected on a network, the IP address it uses, or the like.Information identifying a user consists, for example, of a user ID, IPaddress of the client used by the user, or the like.

The predetermined information provided by the notification enables“another network-connected device” to quickly perform calculations ofusage charges, replenish expendables, and so on.

According to this first aspect, by correcting error in measurementsaccording to predetermined timing, accuracy of measurement ofconsumption of an expendable can be improved, even without the use of asensor able to continuously monitor consumption.

The invention in a second aspect thereof provides a monitoring devicefor monitoring a printer, comprising: a completion determination unitfor determining completion of printing; a measurement unit forcalculating amount consumed of an expendable as relates to printingdetermined to have reached the completion, and a notification unit fornotifying another network-connected device of predetermined informationrelating to the consumed amount.

Here, expendables may include paper or OHP transparency film used duringprinting, for example. The completion determination unit monitors theprinter, and decides whether actual completion of printing has takenplace. “Actual completion of printing” herein refers to a print jobultimately outputting paper or other medium. The measurement unit countsthe number of pages of a print medium determined to have completedprinting.

By so doing, even in the event that, for example, the printerexperiences an error after a print job has been issued, causing printingto halt in mid-operation, it is nevertheless possible to measureconsumed amount for the actually printed portion of the job, and thus toimprove the accuracy of sensing of consumed amount.

The present invention in a third aspect thereof provides a monitoringdevice for monitoring a printer, wherein the printer is a device thatperforms printing by ejecting ink stored in an ink receptacle. Themonitoring device comprises a measurement unit for measuring the amountof ink ejected by the printer during the printing; a correction unitthat, by means of sensing the consumption state of the ink amount by amethod different from the measurement, corrects error occurring in themeasurement result; and a notification unit for notifying anothernetwork-connected device of information relating to the ink amountreflecting the correction.

The measurement unit measures the amount of ink by adding up, by meansof a software application, the ink drop count ejected by the ink head ofthe ink cartridge, and the amount of ink suctioned out duringmaintenance processes.

As the method for sensing the amount of ink consumed, there may beemployed, for example, a technique of producing sympathetic vibrationwithin the ink cartridge by charging and discharging a piezoelectricelement neighboring the ink cartridge, sensing the remaining amount ofink from differences in resonance frequency produced by the sympatheticvibration (technique disclosed in JP2001-147146A). On the basis ofremaining amount of ink sensed by this method, the correction unitperforms correction of the ink use amount measured by the measurementunit.

By so doing, errors in estimated ink consumption due to serviceenvironment can be corrected, making possible measurement with highaccuracy.

The invention in a fourth aspect thereof provides a monitoring devicefor monitoring a printer, comprising a completion determination unit fordetermining completion of printing; a measurement unit for calculatingat least one parameter selected from number of pages of paper used inthe printing determined to have been completed, and amount ofinformation of print data used in the printing determined to have beencompleted; and a notification unit for notifying anothernetwork-connected device of predetermined information relating to theresult of the measurement.

By so doing, it is possible to measure, with a high degree of accuracy,the amount of information or number of pages for which printing hasactually completed, so that when performing billing or the like, billingwill accurately reflect actual number of pages printed or amount ofinformation.

In a monitoring device according to the fourth aspect, there may beemployed an arrangement wherein the completion determination unitcomprises a status acquisition unit for acquiring operating status of aprinter and print data remaining in the corresponding spooler; whereinin the event that no remaining data is present in the spooler and theoperating status of the printer is “ready to print”, a determination ismade that printing has completed.

If there is no remaining print data in the spooler, acquisition of“ready” status by the status acquisition unit can be assumed to indicatethat printing is over. By means of this arrangement, completion ofprinting of print data can be determined in a reliable manner, improvingthe accuracy of detection of completion of printing.

In a monitoring device according to the fourth aspect, there may beemployed an arrangement wherein the print data is in predeterminedformat outputtable in page units; and the completion determination unitdetermines print outcome of the print data in page units.

This predetermined format may be the PDF (registered trademark) format,for example. Print outcome herein includes success or failure to printthe page, as well as, for example, detailed information such as numberof pages done printing, number of pages failing to print, and so on.With this arrangement, print outcome can be monitored closely inindividual page units, making it possible to determine completion ofprinting with greater accuracy.

The invention in a fifth aspect thereof provides a monitoring device formonitoring a printer, wherein the printer is a device that performsprinting by ejecting ink stored in an ink receptacle. The monitoringdevice comprises a measurement unit for measuring the amount of inkejected by the printer during the printing; a correction unit that, bymeans of sensing the consumption state of the ink amount by a methoddifferent from the measurement, corrects error occurring in themeasurement result; a completion determination unit for determiningcompletion of printing; a completion information measurement unit forcalculating at least one parameter selected from number of pages ofpaper determined to have been completed, and amount of information ofprint data of the portion determined to have been completed; and anotification unit for notifying another network-connected device ofinformation relating to the ink amount reflecting the correction, and tooutcome measured by the completion information measurement unit.

This aspect of the invention is equivalent to a combination of the thirdand fourth aspects of the invention. In this way, the various elementsof the invention may be combined as appropriate.

In a monitoring device according to any of the first to fifth aspects,the notification unit may additionally provide notification of billinginformation identifying a payer to be billed on the basis of thecontents of the notification.

Billing information may include, for example, user information, bankaccount number, or other information. By means of this arrangement, thepayer may be identified quickly when billing for consumed amounts ofexpendables and for the amount of printed information, whereby it ispossible to improve transaction efficiency.

A monitoring device according to any of the first to fifth aspects mayfurther comprise a calculation unit for calculating a service fee on thebasis of the consumed amount, the number of sheets of paper, and theamount of information; wherein the notification unit providesnotification of the service fee.

With this arrangement, the amount of information sent by way ofnotification to another device can be reduced, so that the load on thenetwork can be lessened. Additionally, since a user can verify chargesimmediately after completion of printing, convenience may be improved.

In this embodiment, expendables are not limited to ink, and may take anyof various other forms, such as toner, a drum, or the like. In caseswhere quantitative calculation is difficult, it is possible, forexample, to determine degradation in quality on the basis of number oftimes used. As regards expendables measurement of which is triggered bycompletion of printing, these are not limited only to paper or OHPtransparency film, and naturally can include any kind of printablemedium.

The invention may also be constituted on the basis of a transactionmodel wherein consumption of expendables (such as ink) used by a user,as well as amounts of printed documents and of printed information, aremonitored, with notification being provided to an administration serverconnected via a network, so that that the user may be billed accurately,or so that notification of time to replace an expendable may beprovided, or an expendable delivered.

Besides the monitoring device arrangements described above, theinvention in another aspect thereof may take the form of a method formonitoring a printer. Other possible embodiments thereof could include:a computer program for realizing the above; a recorded medium havingsuch a program recorded thereon; or a data signal containing such aprogram and embodied in a carrier wave. The additional elements notedabove may be employed in any of these embodiments.

Where the invention is embodied as a computer program or recorded mediumhaving such a program recorded thereon, it may constitute the entiretyof the program for driving the monitoring device, or only those portionsfor realizing the functions of the invention. Recorded media may includea flexible disk, CD-ROM, DVD-ROM, magnetooptical disk, IC card, ROMcartridge, punch card, printed matter imprinted with symbols such as abar code, a computer internal storage device (RAM, ROM or other memory)or external storage device, or other computer-readable medium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified illustration of a monitoring system in a firstembodiment;

FIG. 2 is an illustration of the inside of the monitoring system in thefirst embodiment;

FIG. 3 is flowchart of a billing information notification process in thefirst embodiment;

FIG. 4 is flowchart of a sheet count sensing process in the firstembodiment;

FIG. 5 is flowchart of a used ink amount measuring process in the firstembodiment;

FIG. 6 is flowchart of a process for acquiring amount of information ofprint data having completed printing in a second embodiment; and

FIG. 7 is flowchart of a charge calculation process in a thirdembodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiments of the invention are described hereinbelowaccording to the following outline.

A. Embodiment 1

A1: System Overview

A2: Internal Arrangement

A3: Billing Information Notification Process

A4: Sheet Count Sensing Process

A5: Ink Amount Measuring Process

B. Embodiment 2

B1: Information Amount Sensing Process

-   -   C. Embodiment 3

C1: Charge Calculation Process

D. Variations

A1: System Overview

FIG. 1 is a simplified illustration of a monitoring system by way of afirst embodiment. As shown in the drawing, an ink jet printer PT has alocal connection to a client computer CL; the client computer CLconnected to a central server SV (hereinafter “server SV”) via theInternet INT. A monitoring system is set up for the client computer CL.In this embodiment, the user is charged according to amounts ofexpendables consumed by printer PT.

Client computer CL queues a print job onto the spooler corresponding tothe printer PT. When the queued print job has been arranged in printorder, it is sent to the printer PT, which commences printing. Clientcomputer CL performs monitoring of completion of printing of the printjob, measurement of the amount of ink used by printer PT, andacquisition of the number of sheets of printer paper. This informationis transmitted via the Internet INT to the server SV, which administersbilling information. On the basis of information received by the serverSV, a process to calculate the charges and request payment from the useris performed. Request for payment can be carried out in any of variousways based on user information preregistered in the server SV, forexample, sending an invoice to a registered address, or debiting theamount from a registered bank account.

Since the client computer CL has been set up as the monitoring systemfor monitoring printer PT, hereinafter the client computer CL will bereferred to as monitoring system 1000. In this embodiment, print jobstake the form of PDF files, which allow determination of completedprinting to be made in page units, with determination of completedprinting being made on a page unit basis.

A2: Internal Arrangement

FIG. 2 is an illustration of the inside of the monitoring system 1000 inthis embodiment. Monitoring system 1000 comprises a main control unit100, a communications unit 101, a billing information processing unit102, a completion determination unit 103, an ink amount measurement unit104, a spooler 105, a job control unit 106, and a job buffer 107. Thesefunctional blocks can be set up in client computer CL by installingsoftware for realizing these functions, and controlled by main controlunit 100. Alternatively, the functional blocks may be constituted byhardware.

Main control unit 100 performs operational control of the functionalblocks of monitoring system 1000. Control herein includes control ofcommunication of information with the outside via the network,acquisition of operating status of connected printer PT and ofconsumption status of expendables during printing by printer PT, and soon.

Job control unit 106 monitors job buffer 107 at predetermined intervals,and sends the job, in the order in which it was input to the job buffer107, to the spooler 105. Spooler 105 transfers the received job in orderto the printer PT.

Once spooler 105 has commenced sending a job to the printer PT, thecompletion determination unit 103 outputs a print start notification.The completion determination unit 103 constitutes part of the billinginformation processing unit 102, and administers information relating tothe printer PT. Information relating to the printer PT includes themodel and status of printer PT. It may also include various other kindsof information, such as printable paper size. Once the completiondetermination unit 103 acquires a print start notification, the statusof the printer PT is checked, along with whether any job data remains inthe spooler 105, and on the basis of the outcome of this check adetermination is made as to whether printing has finished.

The ink amount measurement unit 104 measures the amount of ink used inthe course of printing, from the ink consumption amount and remainingink amount acquired through communication with the cartridge 200 ofprinter PT. Ink consumption amount refers to the amount of inkcalculated during printing; remaining ink amount refers to the remainingamount detected by the sensor.

A simplified illustration of cartridge 200 is included in FIG. 2. At thelower end of cartridge 200 is disposed an ink supply orifice 201 forsupplying ink to the print head of printer PT; at the upper end aredisposed an antenna 202 for communicating with printer PT, and a logiccircuit 203 that includes a sensor SS for sensing remaining ink amount.In this embodiment, sensor SS is a piezoelectric element.

Following is a description of the method for measuring amount of inkconsumed. By means of software, the ink amount measurement unit 104 addsup the amount of ink ejected from ink supply orifice 201, and the amountof ink suctioned out during maintenance of the print head, to arrive atthe amount of ink consumed. This method of measurement will be referredto as Method A; remaining ink amount derived from amount of inkconsumed, acquired by means of Method A, will be referred to asremaining ink amount A. In this embodiment, amount of ink consumed iscalculated by the minute during printing, and stored in memory in logiccircuit 203; however, it could be stored in the monitoring system 1000instead.

Following is a description of the method for measuring remaining inkamount. Using electromagnetic waves received from printer PT, cartridge200 applies voltage to the piezoelectric element of sensor SS. Thisapplication of voltage causes the piezoelectric element of sensor SS tovibrate, producing an elastic wave in the ink. Remaining ink amount canbe sensed on the basis of the reflected wave created when this elasticwave reflects off the surface of the ink, and the back electromotiveforce created in the piezoelectric element by composite vibration ofresidual vibration of the piezoelectric element. This method ofmeasurement will be referred to as Method B; remaining ink amountmeasured by means of Method B will be referred to as remaining inkamount B. Method B does not involve quantitative detection of remainingink amount B; rather, it senses whether a predetermined site, determinedwith reference to the installation location of sensor SS, is below thesurface level of the ink. In this embodiment, the sensor SS is situateda location enabling it to detect whether half or less of the inkremains. In this embodiment, remaining ink amount B is stored in memoryin logic circuit 203; however, it could instead be stored in memoryprovided to the monitoring system 1000.

By sending a predetermined control signal to the cartridge, the inkamount measurement unit 104 acquires consumed ink amount and remainingink amount B. Remaining ink amount A and remaining ink amount B arecompared, and if there is a discrepancy, consumed ink amount iscorrected and handed over to the billing information processing unit102.

On the basis of information received from the completion determinationunit 103 and the ink amount measurement unit 104, the billinginformation processing unit 102 generates notification information fornotification to the server SV. Notification information includesconsumed amounts of expendables, acquired in each functional block, anda user ID for identifying the user. For example, information for anaccount to be debited, the printer MAC address, or other suchinformation useable by the server SV in requesting payment can be usedinstead of, or in addition to, a user ID.

The communications unit 101 exchanges data with other devices throughthe Internet INT. Communications unit 101 sends the notificationinformation created by the billing information processing unit 102 tothe server SV via the Internet INT.

By means of the device arrangement described hereinabove, the monitoringsystem 1000 of this embodiment acquires the true number of sheets forwhich printing has finished, as well as ink use amount actually used inprinting, and notifies the server SV of same, so that the user can bebilled accurately. Following is a description of the process foracquiring amounts of expendables consumed by printer PT and notifying ofbilling information, in the event that a print job has been issued tothe printer PT.

A3: Billing Information Notification Process

FIG. 3 is flowchart of a billing information notification process inthis embodiment. When client CL issues a print job to printer PT (StepS10), the print job is spooled in page units onto the spooler 105, andthen sent in order to the printer PT to commence printing (Step S11).Once printing begins, the monitoring system 1000 monitors theoperational status of the printer PT and remaining data in the spooler105, to detect completion of printing (Step S12), as well as measuringthe amount of ink used (Step S13).

Once printing is finished, monitoring system 1000, on the basis of themeasured amount of ink used, generates information for notifying theserver SV (Step S14), and sends it to the server SV (Step S15).

On the basis of the information received from the monitoring system1000, the server SV calculates the charges, and requests the user forpayment.

A4: Sheet Count Sensing Process

FIG. 4 is flowchart of a sheet count sensing process in the embodiment.This is a process wherein, on the basis of information acquired from theprinter PT and spooler 105, the monitoring system 1000 determines theprinting has finished, and then counts the number of sheets of paper.This process is initiated by transfer of a print job held in job buffer107 to the spooler 105, in page units.

The monitoring system 1000 opens the PDF file of the first job held injob buffer 107, and sends the first page to the spooler 105 (Step S20).Once printing commences, the monitoring system 1000 verifies atpredetermined time intervals whether any print data is remaining in thespooler (Step S21), as well as acquiring the status of the printer PT(Step S22).

Next, on the basis of the status of the printer PT and the remainingdata in the spooler 105, the monitoring system 1000 determines ifprinting has finished (Step S23). If the status is “ready to print,” andthere is no remaining data present in the spooler 105, the monitoringsystem 1000 decides that printing has finished, and adds up the numberof page printed (Step S24). If page printing is not yet finished, theprocess of Steps S21-S23 is repeated.

The monitoring system 1000 next makes a decision as to whether theprinted page is the final page (Step S25), and if it is the final page,determines the number of pages printed, and terminates the process. Ifit is not the final page, in Step S105, the next page is input, and theprocess beginning at Step S21 is repeated (Step S26).

A5: Ink Amount Measuring Process

FIG. 5 is flowchart of a used ink amount measuring process in theembodiment. The process commences after printing of the last page of aprint job has been completed.

First, the monitoring system 100 acquires the amount of ink consumed, asmeasured using Method A (Step S30). Next, using remaining ink amount Acalculated on the basis of this amount of ink consumed, a decision ismade as to whether the condition “|remaining ink amount−½|<α” (StepS31). In the embodiment, this value a is arbitrary.

In the event that remaining ink amount A meets the condition “|remainingink amount−½|<α”, monitoring system 1000 senses remaining ink amount Busing method B (Step S32). Remaining ink amount A and remaining inkamount B are then compared, and a decision is made as to whetherremaining ink amount A is correct, that is, whether the differencebetween the two amounts is within a predetermined permissible range(Step S34). In the event that remaining ink amount A has been found tohave error and be incorrect, remaining ink amount A is corrected to thevalue of remaining ink amount B; the amount of ink consumed is correctedas well (Step S35). The monitoring system 1000 deems this correctedresult to be the amount of ink used by the user, and terminates themeasuring process (Step S36).

In Step S31, if remaining ink amount A does not meets the condition“|remaining ink amount−½|<α”, the amount of ink consumed acquired inStep S30 is deemed to be the amount of ink actually used by the user,whereupon the measuring process terminates (Step S36).

In Step S34, in the event of a decision that remaining ink amount A iscorrect, the amount of ink consumed acquired in Step S30 is deemed to bethe amount of ink actually used by the user, whereupon the measuringprocess terminates (Step S36).

According to this embodiment, completion of printing of a print job canbe ascertained in detail in page units. Additionally, error in inkamount calculated using Method A can be corrected at the point in timethat half of the ink has been consumed, and it becomes possible toaccurately measure the amount of ink used in printing. By so doing, evenif error should occur, the amount of ink that would have been consumedin printing pages that failed to print can be omitted, without having tocount the number of pages that failed to print, so that the user can beaccurately charged fro the number of sheets of paper printed and theamount of ink used.

B. Embodiment 2

In Embodiment 1, there was shown an example wherein billing is performedthrough notifying the server SV of consumed amounts of two expendables,namely, the number of sheets of paper having completed printing, and theamount of ink used. In Embodiment 2, billing is performed by notifyingthe server of the amount of information of print data having completedprinting, for example, the number of bytes. In this embodiment, systemdesign is the same as in Embodiment 1, and print jobs take the form ofPDF files that allow completion of printing to be determined in pageunits.

FIG. 6 is flowchart of a process for acquiring amount of information ofprint data having completed printing in a second embodiment. Theprocesses of Step S100-Step S103 are similar to the processes of StepS20-Step S23 of Embodiment 1, and need not be described here.

In Step S103, in the event it is decided that printing of a page hascompleted, the monitoring system adds up the amount of information forthe page that has completed printing (Step S104), and then makes adecision as to whether this page is the final page (Step S105). If it isthe final page, the amount of information printed is verified, and theprocess terminates. If it is not the final page, the next page is sentthe spooler 105, returning to Step S101 and looping the process (StepS106).

According to this embodiment, billing of a user can be performed bynotifying the server SV of the amount of information of print datahaving completed printing. By so doing, it becomes possible to assessthe same charge where, for example, print data for an amount ofinformation that would fit onto a single page prints out onto two pages,due to layout. Also, when printing print data that contains a largeamount of information, since the printer will inevitably be occupied foran extended period, the charges levied may take into consideration theduration the printer is so occupied.

C. Embodiment 3

C1: Charge Calculation Process

In Embodiment 1 and Embodiment 2, billing calculations are performed bythe server SV, on the basis of information provided by notification fromthe monitoring system 1000. In Embodiment 3, billing calculations areperformed by the monitoring system 1000, which then notifies the serverSV of the calculated charges. The system overview in this embodiment issimilar to that in Embodiment 1 and Embodiment 2. However, the billinginformation processing unit 102 performs the billing calculations on thebasis of information received from the completion determination unit 103and ink amount measurement unit 104.

FIG. 7 is flowchart of a charge calculation process in Embodiment 3. Theclient CL initiates the process at the point in time that a print job isissued. The processes of Step S201-Step S204 are similar to the processof Step S10-Step S13 of Embodiment 1, and need not be described here.

On the basis of information received from the completion determinationunit 103 and ink amount measurement unit 104, the billing informationprocessing unit 102 calculates the charges and creates billinginformation for notification to the server SV (Step S205). The billinginformation includes the calculated charges and a user ID identifyingthe user. For example, account information for the account to bedebited, the MAC address of the printer, or some other informationenabling the server to make request for payment could be used instead ofa user ID, or in addition to a user ID.

Via the communications unit 101, the billing information processing unit102 notifies the server SV of the created billing information (StepS206). Using the billing information received from the monitoring system1000, the server SV requests the user for payment.

By so doing, the user can verify the charges immediately aftercompletion of printing, so that convenience is improved. Also, since theamount of information sent by way of notification the server SV can bereduced, the load on the network can be lessened, and since billingcalculations need not be made on the server, the load on the server maybe reduced as well.

In Embodiments 1-3, the information acquired by the monitoring system1000 was used for billing purposes, but is not limited thereto. Theinvention is applicable also to various other processes such asascertaining consumption status of expendables, notification of time toreplace expendables, delivery of expendables, and so on. Expendablesherein are not limited to ink, and may take any of a number of otherforms such as toner, drums, or the like. For expendables for whichquantitative calculation is difficult, it is possible, for example, todetermine degradation in quality on the basis of number of times used.As regards expendables measurement of which is triggered by completionof printing, these are not limited only to paper or OHP transparencyfilm, but may be any of various printable media.

In Embodiment 2, completion of printing is determined in page units, butcould instead be determined in job units.

While the invention has been shown and described hereinabove throughcertain preferred embodiments, it is not limited thereto and may assumeany of various other arrangements without departing from the scope andspirit thereof. For example, the above control functions could berealized through software, or through hardware.

D. Variations

D1. Variation 1:

In Embodiments 1-3, the printer PT receives print jobs from the clientcomputer CL, but this arrangement is not limiting. The printer PT couldinstead be connected to a network, and receive print jobs from variouscomputers on the same network. In this case, it is preferable for theprinter PT to have installed therein a control unit composed of amicrocomputer comprising a CPU, RAM and ROM or other memory, so that themonitoring system may be implemented within the printer. By so doing,the load on the client computer CL can be reduced.

D2. Variation 2:

In Embodiments 1-3, processes relating to billing are performed by theserver, but this arrangement is not limiting. Instead, print jobs couldbe issued from the server SV, which would function as a job issuingdevice for executing printing. Alternatively, a print job could beissued to the server SV from a mobile terminal such as a cell phone,with printing being performed by the printer PT under the control of theserver SV. By means of this arrangement, even if printing is carried outfrom a remote location, amounts of expendables consumed by printer PTmay nevertheless be measured efficiently.

D3. Variation 3:

In Embodiments 1-3, the monitoring system 1000 is implemented on theclient computer CL, but this arrangement is not limiting. Instead, themonitoring system 1000 could be implemented on the server SV, andconsumed amounts of expendables monitored via the Internet INT. By meansof this arrangement, the load on the client computer CL and the printerPT can be reduced, and processing efficiency improved.

D4. Variation 4:

In Embodiments 1-3, consumed amounts of expendables are transmitted tothe server SV via the Internet INT; however, these may instead beemployed in an arrangement whereby consumed amounts of expendables aremonitored within a LAN (local area network). Since the present inventionis not limited to billing purposes, implementation thereof for thepurpose of overall monitoring of consumed amounts of expendables byprinters in a LAN, and notifying of time to replace or reorderexpendables, for example, is also possible.

According to the monitoring system of the present invention, amounts ofexpendables consumed by a printer can be measured accurately, andbilling for consumed amounts, administration of expendables, or otherfunctions carried out efficiently.

INDUSTRIAL APPLICABILITY

The present invention may be utilized for monitoring the status ofprinter expendables and printer service conditions, via a network.

1. A monitoring device for monitoring status of expendables for aprinter connected to a network, the device comprising: a measurementunit for measuring amount of an expendable consumed during execution ofprinting by the printer; a correction unit that, by means of sensingconsumed amount of the expendable using a method different from themeasurement, corrects error occurring in the measurement result; and anotification unit for notifying another network-connected device ofinformation relating to the consumed amount reflecting the correction.2. A monitoring device for monitoring status of expendables for aprinter connected to a network, the device comprising: a completiondetermination unit for determining completion of printing; a measurementunit for calculating amount consumed of an expendable as relates toprinting determined to have reached the completion; and a notificationunit for notifying another the network-connected device of predeterminedinformation relating to the consumed amount.
 3. A monitoring device formonitoring status of expendables for a printer connected to a network,wherein the printer is a device that performs printing by ejecting inkstored in an ink receptacle, and the monitoring device comprises: ameasurement unit for measuring amount of ink ejected by the printerduring the printing; a correction unit that, by means of sensingconsumption state of the ink amount by a method different from themeasurement, corrects error occurring in the measurement result; and anotification unit for notifying another network-connected device ofinformation relating to the ink amount reflecting the correction.
 4. Amonitoring device for monitoring status of expendables for a printerconnected to a network, the device comprising: a completiondetermination unit for determining completion of printing; a measurementunit for calculating at least one parameter selected from number ofsheets of paper used in the printing determined to have been completed,and amount of information of print data used in the printing determinedto have been completed; and a notification unit for notifying anothernetwork-connected device of predetermined information relating to theresult of the measurement.
 5. A monitoring device according to claim 4wherein the completion determination unit comprises a status acquisitionunit for acquiring operating status of the printer and print dataremaining in a corresponding spooler; wherein in the event that noremaining data is present in the spooler and the operating status of theprinter is ready to print, a determination is made that printing hascompleted.
 6. A monitoring device according to claim 5 wherein the printdata is in predetermined format outputtable in page units; and thecompletion determination unit determines the print completion of theprint data in page units.
 7. A monitoring device for monitoring statusof expendables for a printer connected to a network, wherein the printeris a device that performs printing by ejecting ink stored in an inkreceptacle, and the monitoring device comprises: a measurement unit formeasuring amount of ink ejected by the printer during the printing; acorrection unit that, by means of sensing the consumption state of theink amount by a method different from the measurement, corrects erroroccurring in the measurement result; a completion determination unit fordetermining completion of printing; a completion information measurementunit for calculating at least one parameter selected from number ofsheets of paper used in the printing determined to have been completed,and amount of information of print data used in the printing determinedto have been completed; and a notification unit for notifying anothernetwork-connected device of predetermined information relating to atleast one parameter selected from the ink amount reflecting thecorrection, the number of sheets of paper, and the amount ofinformation.
 8. A monitoring device according to any of claims 1 to 7wherein the notification unit additionally provides notification ofbilling information that identifies a payer to be billed based oncontents of the notification.
 9. A monitoring device according to any ofclaims 1 to 7, further comprising a calculation unit for calculating aservice fee based on the consumed amount, the number of sheets of paper,and the amount of information; wherein the notification unit providesnotification of the service fee.
 10. A monitoring method for monitoringstatus of expendables for a printer connected to a network, the methodcomprising the steps of: measuring amount of an expendable consumedduring execution of printing by the printer; by means of sensingconsumption status of the expendable using a method different from themeasurement, correcting error occurring in the measurement result; andnotifying another the network-connected device of information relatingto the consumed amount reflecting the correction.
 11. A monitoringmethod for monitoring status of expendables for a printer connected to anetwork, the method comprising the steps of: determining completion ofprinting; calculating amount consumed of an expendable as relates to theprinting determined to have reached the completion, and notifyinganother the network-connected device of predetermined informationrelating to the consumed amount.
 12. A recording medium having recordedthereon a computer program for causing a computer to monitor status ofexpendables for a printer connected to a network, the medium havingrecorded thereon a computer program for causing a computer to performthe functions of: measuring amount of an expendable consumed duringexecution of printing by the printer; by means of sensing consumptionstatus of the expendable using a method different from the measurement,correcting error occurring in the measurement result; and notifyinganother network-connected device of information relating to the consumedamount reflecting the correction.
 13. A recording medium having recordedthereon a computer program for causing a computer to monitor status ofexpendables for a printer connected to a network, the medium havingrecorded thereon a computer program for causing a computer to performthe functions of: determining completion of printing; calculating amountconsumed of an expendable as relates to the printing determined to havereached the completion, and notifying another the network-connecteddevice of predetermined information relating to the consumed amount.